dajiaoyan-scanner/DaJiaoYan/Utils/ImageUtils.cs

using OpenCvSharp;
using OpenCvSharp.Extensions;
using System;
using System.Drawing;
using System.IO;

namespace DaJiaoYan.Utils
{
    internal class ImageUtils
    {
        internal static Mat Read(string filename, ImreadModes mode = ImreadModes.AnyColor)
        {
            var res = Cv2.ImRead(filename, mode);
            if (res == null || res.Width < 1 || res.Height < 1)
            {
                // 判断图片异常
                try
                {
                    Bitmap bitmap = new Bitmap(filename);
                    res = ToMat(bitmap);
                }
                catch { }

            }
            return res;
        }
        /// <summary>
        /// image 转 mat
        /// </summary>
        /// <param name="image"></param>
        /// <returns></returns>
        internal static Mat ToMat(Image image)
        {
            Mat mat = null;
            if (image != null)
            {
                Bitmap bmp = new Bitmap(image);
                mat = BitmapConverter.ToMat(bmp);
                bmp.Dispose();
            }
            return mat;
        }

        /// <summary>
        /// 从 stream 转 mat
        /// </summary>
        /// <param name="stream"></param>
        /// <returns></returns>
        internal static Mat ToMat(Stream stream)
        {
            Mat mat = null;
            if (stream != null && stream.Length > 0)
            {
                mat = Mat.FromStream(stream, ImreadModes.AnyColor);
            }
            return mat;
        }


        /// <summary>
        /// 转Base64
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        internal static string ToBase64(string filename)
        {
            string res = "";
            try
            {
                using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read))
                {
                    byte[] buffer = new byte[fs.Length];
                    fs.Read(buffer, 0, (int)fs.Length);
                    res = Convert.ToBase64String(buffer);
                }
            }
            catch { }
            return res;
        }


        internal static void Red2OtherColor(ref Mat img, Scalar scalar, int minThreshold = 10, int maxThreshold = 40)
        {
            Cv2.CvtColor(img, img, ColorConversionCodes.BGR2HSV);

            Mat mask0 = new Mat(), mask1 = new Mat(), mask;

            Cv2.InRange(img,
                new Mat(1, 3, MatType.CV_32S, new Scalar(0, maxThreshold, maxThreshold)),
                new Mat(1, 3, MatType.CV_32S, new Scalar(minThreshold, 255, 255)),
                mask0);

            Cv2.InRange(img,
                new Mat(1, 3, MatType.CV_32S, new Scalar(150, maxThreshold, maxThreshold)),
                new Mat(1, 3, MatType.CV_32S, new Scalar(180, 255, 255)),
                mask1);

            mask = mask0 + mask1;
            Cv2.CvtColor(img, img, ColorConversionCodes.HSV2BGR);
            img.SetTo(scalar, mask);
            mask0?.Dispose();
            mask1?.Dispose();
            mask?.Dispose();
        }

    }

}